Daemon ignoring "--log-opt tag=" setting

Hello,

I do have a docker.conf on Ubuntu 16.04 for system.d that looks like this:

[Service]
ExecStart=
ExecStart=/usr/bin/docker daemon -H tcp://127.0.0.1:2376 --log-driver syslog --log-opt tag='docker/{{.Name}}'

I expected the tag in var/log/syslog to look like docker/<name> but it still is using {{.Name}}/{{.ID}}

Is there anything else I have to change?

Kind regards,
Sascha